Genetically modified plants used as pollution pumps

Modified plants are to be used as a new weapon to clean sites contaminated by spent explosives.

In a new development in the field of bioremediation the plants have been genetically altered by scientists from the University of York to act as giant pumps, sucking pollutants from the soil.

The research was led by Professor Neil Bruce from the university's Centre for Novel Agricultural Products and uses micro-organisms found in soil to turn trees and smaller plants into highly-effective pollution-busters.

Field tests have been carried out on large tracts of land in the USA where the widely-used and highly toxic explosive RDX has contaminated both the soil and groundwater.

The scientists identified a naturally-occurring micro organism in the soil which breaks down the explosives to use the nitrogen to grow but found it was not degrading the RDX fast enough to prevent contamination.

To solve the problem the team isolated the enzyme in the bacteria that was breaking down the toxic explosive and genetically inserted it into plants, which can do the job much quicker.

"This is a sustainable, low maintenance and low cost process which has the potential to clean up large areas of land in military training ranges or industrial sites," said Professor Bruce.

"We have taken that activity from the bacteria and put it in plants with large amounts of biomass. A tree, for instance, is effectively a big pump, seeking out water, and if we can redeploy the enzyme which degrades the explosive making it harmless, it combines the capabilities of soil bacteria with the high biomass and uptake properties in plants.

"We are using an enzyme already existing in the soil but putting it into a more efficient machine to biodegrade the RDX."

The team is hopeful the technique can also be used to modify plants to absorb other organic pollutants.